In a typical method for producing light emitting devices such as LED light sources, a plurality of LED elements are fixed on one substrate by die bonding or the like, and then the substrate is diced for every one or two or more LED elements and mounted on a printed circuit board (for example, Patent document 1). In such a production process, reflectors for enhancing luminous efficiency of the LED elements are provided around the LED elements.
Patent document 2 discloses a technique of forming a layer of a light reflecting resin serving as a reflector before the LED elements are separated by dicing, and then performing the dicing. Moreover, various techniques of using a thin metal plate as a substrate for carrying LED elements and utilizing the metal plate as a reflector are also proposed (Patent documents 3 and 4). When a metal plate is used as a substrate of LED elements, it is essential to provide a slit for insulating a part for connecting one electrode of an LED element (die bonding pad) and a part for connecting the other electrode (wire bonding pad). In this case, it is necessary to connect the metal plates separated by the slit during the production.
In the technique described in Patent document 3, a thin metal plate is first subjected to a press processing to form a reflector, a die bonding pad and a wire bonding pad are separated with a slit, and an insulating resin such as an epoxy resin in which silica or the like is dispersed is flown over the back face of the thin metal plate. Destruction of the connection is thereby prevented at the time of separation of LED elements formed on the metal substrate by dicing.
In the technique described in Patent document 4, both ends of a thin metal plate are bent to have a section of a right-angled U-shape to secure strength, and the portions on both sides of the slit are connected with an insulating masking tape.
[Prior Art References]
[Patent Documents]
    Patent document 1: Japanese Patent Unexamined Publication (KOKAI) No. 2006-108341    Patent document 2: Japanese Patent Unexamined Publication No. 2006-245626    Patent document 3: Japanese Patent No. 3447604    Patent document 4: Japanese Patent Unexamined Publication No. 2002-314148